This invention relates generally to a combustor and specifically to a combustor including features reducing nitrous oxide (NOx) emissions.
Conventional gas turbine engines include a combustor for mixing and burning a fuel air mixture to produce an exhaust gas stream that turns a turbine. Conventional combustors operate near stoichiometric conditions in the primary zone. Such conditions produce higher than desired combustor temperatures. The high combustor temperatures produce greater than desired amounts of nitrous oxide. Environmental concerns and regulation have created the demand for gas turbine engines with reduced nitrous oxide emissions.
Current combustors utilize many different configurations to optimize burning of fuel within the combustor. Many of these configurations include devices for initiating swirl of the fuel and air mixture within the combustor. Such devices improve the efficiency of fuel burning within the combustor. However, each of these devices requires a compromise of the two desirable conditions. That is, during the starting condition the fuel-air ratio is not exactly as would otherwise be desired because of the performance requirements required of the gas turbine engine under full load conditions. As appreciated, the compromise between optimal starting conditions and optimal engine operating conditions results in sacrifices being made for each engine operating condition.
Accordingly, it is desirable to develop a combustor that operates at a reduced temperature to reduce nitrous oxide emissions while providing desired starting and operating performance.